1). Field of the Invention
This invention relates to a method of testing microelectronic dies.
2). Discussion of Related Art
Integrated circuits are usually manufactured in and on semiconductor wafers. Such a semiconductor wafer is subsequently cut into individual dies, each die carrying a respective integrated circuit. Cutting of a wafer into individual dies is commonly referred to as “dicing” or “singulation.”
Once the individual dies are cut from the wafer, it is often advantageous to test the integrated circuit in each die before the packaging of the die. The added expense of packaging of the die can be avoided by first identifying defects in the die. Identification of defects is particularly important for multiple-die assemblies, where one defective die can compromise the value of the entire assembly.
One way of testing a singulated unpackaged die is to temporarily insert the die into a retaining formation in a die carrier body of a die carrier. A plurality of die contacts in the retaining formation make contact with respective ones of a plurality of terminals on the die. External die carrier contacts are electrically connected to the die contacts, and provide surfaces to which electric contact can be made for purposes of providing signals between the die carrier contacts and the terminals on the die.
The die carrier is then inserted into a socket. The socket has a plurality of electrically conductive pins which connects to a burn-in board. The socket also has a plurality of socket contacts that are electrically connected to the pins and make contact with the die carrier contacts. Electric current can thus conduct through the burn-in board connectors and the socket contacts to the die carrier contacts. An electric path is thereby established between the burn-in board and the unpackaged die, and can be used for testing the integrated circuit in the die.
A few types of sockets exist that are used for testing thin small-outline package (TSOP) electronic assemblies. A TSOP is a package having a microelectronic die that is inserted within a mold and having a plurality of 145 micron thin electric leads extending from opposing sides thereof. No die carrier has been designed for use within a TSOP-type socket.
The sockets are typically located in rows and columns on a burn-in board. Tooling is required to remove all the die carriers from the sockets, open the die carriers, replace dies that have been tested with untested dies, close the die carriers, and replace the die carriers in the sockets. The extra tooling increases cost and makes the overall die replacement process more complex.